Production of pure 1-nitroanthraquinone

ABSTRACT

Production of pure 1-nitroanthraquinone from nitroanthraquinone mixtures by treating the mixture in an organic aprotic solvent with a primary or secondary amine or a mixture of the same. A pure 1-nitroanthraquinone in which practically no dinitroanthraquinone or other byproducts can be detected is obtained in a high yield. The 1-aminoanthraquinone obtained from this 1-nitroanthraquinone is suitable for all dye syntheses.

United States atent 1 Bantel et al.

[ 1 PRODUCTION OF PURE l-NITROANTHRAQUINONE [75] Inventors: Karl-Heinz Bantel, Ludwigshafen;

Heinz Eilingsfeld, Frankenthal, both of Germany [73] Assignee: Badische Anilin- & Soda-Fabrik Aktiengesellschaft, Ludwigshafen, Rhine, Germany 22 Filed: June 25,1973

211 Appl. No.: 373,131

[30] Foreign Application Priority Data July 1, 1972 Germany 2232446 [52] U.S. Cl. 260/369, 260/378- [51] Int. Cl C09b 1/00 [58] Field 01 Search 260/369 [56] References Cited UNITED STATES PATENTS 3,766,222 10/1973 Hartwig et al. 260/369 Feb. 25, 1975 FOREIGN PATENTS OR APPLICATIONS 2,142,100 3/1972 Germany 260/369 Primary ExaminerLorraine A. Weinberger Assistant ExaminerE. Jane Skelly Attorney, Agent, or Firm.lohnston, Keil, Thompson & Shurtleff [57] ABSTRACT 13 Claims, N0 Drawings PRODUCTION OF PURE ITRAN R Q 0 E The invention relates to a process for the production of pure l-nitroanthraquinone.

Mixtures of different compounds are always obtained in the nitration of anthraquinone. Mononitration cannot be carried out uniformly: l-nitroanthraquinone is only obtained contaminated with 2-nitroanthraquinone and various dinitro compounds. In the case of nitrations in concentrated sulfuric acid products are obtained as a rule which contain only about 60 to 75% by weight of l-nitroanthraquinone.

Since the tinctorial properties of the dyes which have been prepared from secondary products of lnitroanthraquinone are often adversely affected by impurities present in the starting material it is desirable to start from the purest possible l-nitroanthraquinone.

It is an object of the present invention to recover pure l-nitroanthraquinone from nitration products of anthraquinone obtained by conventional nitration methods.

We have found that l-nitroanthraquinone is obtained in a good yield and in excellent purity by treating a nitroanthraquinone mixture containing 1- nitroanthraquinone in an organic solvent with a primary amine, a secondary amine or a mixture of the two. The undesired byproducts from the nitration are converted in this treatment into more easily soluble compounds and can therefore be separated from the unreacted l-nitroanthraquinone. It is surprising that the byproducts should undergo this conversion while I- nitroanthraquinone is substantially or wholly unaffected.

Nitroanthraquinone mixtures for subjection to the purification process of the invention may be for example mixtures obtainable by prior art nitration methods which as a rule contain only up to 75% by weight of lnitroanthraquinone. Mixtures which have a higher proportion of l-nitroanthraquinone are naturally more easily purified.

The primary and/or secondary amines to be used according to the invention may be aliphatic, cycloaliphatic. araliphatic or saturated heterocyclic. For economical and technical reasons it is recommended that liquid commercially available amines of a boiling point more than 50C should be used. Monoalkylamines and dialkylamines whose alkyl groups may bear hydroxy, alkoxy, amino or substituted amino as substituents and also saturated N-heterocycles are particularly suitable. Specific examples are: n-propylamine, di-npropylamine, monobutylamine, dibutylamine, di-(2- ethylhexyl)-amine, mono-2-ethylhexylamine, N-butyl-2-ethylhexylamine, Z-methoxyethylamine, di-(2-methoxyethyl)-amine, 2-ethoxyethylamine, 3- methoxypropylamine, cyclohexylamine, benzylamine, phenylethylamine, aminomethylcyclopentylamine, 3- cyclohexylaminopropylam ine, l-diethylamino-4- aminopentane, 3-dimethylaminopropylamine, 2-diethylaminoethylamine, monomethylethanolamine, monoethylcthanolamine and aminoethylethanolamine.

Pyrrolidinc, piperazinc, N-methylpiperazine and N-B-hydroxyethylpiperazine are also suitable.

Examples of preferred amines are: ethanolamine, dicthanolamine, butylaminc. morpholine and piperidine and of these morpholine is particularly preferred because in the treatment it gives a particularly pure 1- nitroanthraquinone in a high space-time yield.

The amount of amine to be used depends on the nature and amount of the impurities. it is convenient to use from 0.7 to 4 moles, preferably from 1.5 to 3 moles, of amine per mole of dinitro compound present in the mixture. The use of larger amounts of amine is possible but does not result in any further advantage as regards purification effect.

The solvent used is an aprotic organic solvent in which l-nitroanthraquinone is substantially insoluble but in which the products formed with the amine are soluble.

It has been found that particularly suitable solvents include halogenated aliphatic and aromatic hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, l,l-dichloroethane, l,2-dichloroethane, trichloroethane, tetrachloroethane, tetrachloroethylene, dichloropropane, dibromoethane, chlorobenzene, dichlorobenzene, trichlorobenzene, bromobenzene, chloronaphthalene and aliphatic N,N-dialkylcarboxamides, particularly those of propionic acid, acetic acid and especially of formic acid, and also N- methylpyrrolidone or mixtures of these solvents. Anisole and nitrobenzene are examples of further useful solvents.

Examples of preferred solvents are: N,N-dimethylformamide, N-methylpyrrolidone, l,l-dichloroethane, l,2-dichloroethane, dichloropropane, anisole, nitrobenzene, chlorobenzene and chloronaphthalene of which N,N-dimethylformamide and N- methylpyrrolidone are especially preferred because of their good solvency for the conversion products of dinitroanthraquinones.

The amount of solvent used may be varied within wide limits. The amount used as a rule (based on the nitroanthraquinone mixture) is 0.5 to about 10 times, preferably from 0.7 to 3.0 times the weight. It depends on the composition of the nitroanthraquinone mixture to be purified and on the solubility and amount of the amine conversion products formed.

The reaction is generally carried out at a temperature of from 40 to 250C and the preferred temperature range is from to C. When a temperature below 70C is used the reaction period is as a rule longer and at temperature above 150C and especially at above 200C there is a risk that undesirable byproducts will be formed.

A convenient procedure consists in freeing the nitroanthraquinone mixture from any adherent water by drying or by washing with a lower alcohol or ketone such as methanol, isopropanol or acetone and then stirring it with the amine in an organic solvent at elevated temperature. The nitroanthraquinone mixture may also be brought together as an aqueous paste with the solvent, any adherent water distilled off azeotropically and the amine then added and the whole stirred again at elevated temperature.

To work up the reaction mixture it is conveniently allowed to cool to room temperature and the precipitate is suction filtered; it consists of pure 1- nitroanthraquinone.

l-nitroanthraquinone obtained by the new process may be reduced by conventional methods to laminoanthraquinone which is outstandingly suitable for the production of dyes and dye precursors.

Another advantage of the process of the invention is i EXAMPLE 1 3.5 parts of morpholine is added to a mixture of 25 parts of l-nitroanthraquinone (about 75% purity, the remainder consisting of about 3 to of 1,5-dinitro-, 3 to 5% of l,8-dinitro-, of 1,6-dinitro-, 1,7-dinitroand 2,7-dinitroanthraquinones and 2- nitroanthraquinone) and 40 parts of N,N-dimethylformamide and the whole is stirred for 3 hours at 100C. After cooling to C the precipitate is suction filtered and washed first with a little cold N,N-dimethylformamide and then with water. After drying 16.0 parts of pure l-nitroanthraquinone is obtained which can be reduced by conventional methods to pure 1- aminoanthraquinone.

The yield of l-nitroanthraquinone is equivalent to 85% of theory and the purity of l-aminoanthraquinone prepared therefrom is higher than 96%.

EXAMPLE 2 4.5 parts of piperidine is added to a mixture of parts of l-nitroanthraquinone of the composition specified in Example 1 and 40 parts of nitrobenzene and the whole is stirred for 3 hours at 100C. After cooling to 20C the precipitate is suction filtered, washed first with cold methanol until devoid of nitrobenzene and then with water and dried. 15.6 parts of pure 1- nitroanthraquinone is obtained which can be converted by a conventional method into l-aminoanthraquinone. The yield of l-nitroanthraquinone is 83% of theory and the purity of l-aminoanthraquinone prepared therefrom is higher than 95%.

EXAMPLE 3 4.5 parts of morpholine is added to a mixture of 25 parts of l-nitroanthraquinone (composition as in Example l) and 50 parts of chlorobenzene and the whole is stirred for another 4 hours at 120C and then cooled to 20C. The precipitate is suction filtered, washed free from chlorobenzene with a little acetone and then with water and dried. 16.2 parts of pure 1- nitroanthraquinone is obtained which can be reduced to l-aminoanthraquinone by a conventional method. The yield of l-nitroanthraquinone is equivalent to 86% of theory and the purity of l-aminoanthraquinone prepared therefrom is more than 96%.

EXAMPLE 4 3.7 parts of n-butylamine is added to a mixture of 25 parts of l-nitroanthraquinone of the composition specified in Example 1 and 80 parts of 1,2-dichloroethane and the whole is stirred for six hours at 84C and then cooled to 20C. The precipitate is suction filtered, washed free from solvent with water and dried. 16.7 parts of pure l-nitroanthraquinone is obtained, i.e., a yield of 89% of theory.

EXAMPLE 5 4.4 parts of morpholine is added to a mixture of 25 parts of l-nitroanthraquinone of the composition specified in Example 1 and parts of anisole and the whole is stirred for 3 hours at 120C and then cooled to 20C. The precipitate is suction filtered, washed with cold methanol until it is devoid of anisole and dried. 15.3 parts of l-nitroanthraquinone is obtained, i.e. 81% of theory. l-aminoanthraquinone prepared therefrom by a conventional method has a purity of more than EXAMPLE 6 5.3 parts of diethanolamine is added to a mixture of 25 parts of l-nitroanthraquinone of the composition specified in Example 1 and 45 parts of N,N-dimethylformamide and the whole is stirred for 3 hours at C and then cooled to room temperature. The precipitate is suction filtered, washed first with a little cold N,N-dimethylformamide and then with water until devoid of solvent and then dried. 16.7 parts of pure 1- nitroanthraquinone is obtained, i.e. 89% of theory.

EXAMPLE 7 20 parts of morpholine is added to a mixture of 100 parts of l-nitroanthraquinone (about 65% of lnitroanthraquinone, from 5 to 8% of 1,5-dinitro-, from 5 to 8% of l,8-dinitro-, about 17% of 1,7-dinitroand 2,7-dinitroanthraquinone and a little 2- nitroanthraquinone) in 160 parts of N,N-dimethylformamide and the whole is stirred for 4 hours at C and then cooled to 20C. The precipitate is suction filtered and washed, first with a little cold N,N-dimethylformamide and then with water. After drying 55 parts of pure l-nitroanthraquinone is obtained.

EXAMPLE 8 7 parts of morpholine is added to a mixture .of 50 parts of l-nitroanthraquinone having the composition specified in Example 7 and 50 parts of N- methylpyrrolidone and the whole is stirred for 3 hours at 100C and then allowed to cool. The precipitate is suction filtered and washed with 25 parts of N- methylpyrrolidone and then with 50 parts of methanol and finally with water.

The yield is 29.5 parts of l-nitroanthraquinone containing less than 0.4% of dinitroanthraquinone and 2- nitroanthraquinone.

EXAMPLE 9 The procedure given in Example 8 is adopted but 10.5 parts of 2-ethylhexylamine is used instead of 7 parts of morpholine. After working up 27 parts of 1- nitroanthraquinone is obtained which contains less than 0.4% of dinitroanthraquinones and 2- nitroanthraquinone.

EXAMPLE 10 7.5 parts of 3-methoxypropylamine is added to a mixture of 50 parts of l-nitroanthraquinone (containing about 75% of l-nitroanthraquinone, about 3 to 5% of l,S-dinitroanthraquinone, 3 to 5% of 1,8- dinitroanthraquinone and 10% of 1,6-, 1,7- and 2,7- dinitroanthraquinones and 2-nitroanthraquinone) and 50 parts of N-methylpyrrolidone and the mixture is stirred for 3 hours at 100C and then allowed to cool. The precipitate is suction filtered and washed with 25 parts of N-methylpyrrolidone, then with 50 parts of methanol and finally with water.

The yield is 28.2 parts of l-nitroanthraquinone V which contains less than 0.4% of dinitroanthraquinones and 2-nitroanthraquinone.

EXAMPLE 1 1 10.5 parts of 2-ethylhexylamine is added to a mixture of 50 parts of l-nitroanthraquinone having the composition specified in Example and 50 parts of N,N-dimethylformamide and the whole is stirred for 3 hours at 100C and then allowed to cool. The precipitate is suction filtered and washed with 25 parts of N,N-dimethylformamide, then with 50 parts of methanol and finally with water.

The yield is 29.7 parts of l-nitroanthraquinone which contains less than 0.4% of dinitroanthraquinones and 2-nitroanthraquinone.

EXAMPLE 12 The procedure described in Example 11 is followed but 7.5 parts of 3-methoxypropylamine is used instead of Z-ethylhexylamine. After working up 28.4 parts of l-nitroanthraquinone is obtained which contains less than 0.3% of dinitroanthraquinones and 2- nitroanthraquinone.

EXAMPLE 13 The procedure described in Example 11 is followed but 10 parts of N-methylbenzylamine is used instead of 2-ethylhexylamine. After working up 29.8 parts of lnitroanthraquinone is obtained which contains less than 0.4% of dinitroanthraquinones and 2- nitroanthraquinone.

We claim:

phatic or aromatic halogenated hydrocarbon, nitrobenzene, anisole, an aliphatic N,N-dialkylcarboxamide or a mixture thereof is used as the organic solvent.

3. A process as claimed in claim 1 wherein N,N-dimethylformamide, N-methylpyrrolidone, anisole, chlorobenzene, nitrobenzene or 1,2- dichloroethane is used as the solvent.

4. A process as claimed in claim 1 wherein ethanolamine, diethanolamine, butylamine, piperidine, morpholine or a mixture thereof is used as the amine.

5. A process as claimed in claim 1 wherein the amount of aprotic organic solvent is from 0.5 to 10 times the weight of the nitroanthraquinone mixture.

6. A process as claimed in claim 3 wherein the amount by weight of solvent is from 0.7 to 3.0 times the weight of the nitroanthraquinone mixture.

7. A process as claimed in claim 4 wherein from 1.5 to 3 moles of said amine or amine mixture is used per mole of dinitro compounds present in the crude mixture.

8. A process as claimed in claim 1 wherein the treatment with the amine is carried out at a temperature of from 40 to 200C.

9. A process as claimed in claim 3 wherein the treatment is carried out at a temperature of from to C.

10. A process as claimed in claim 7 wherein the treat- I ment is carried out at a temperature of from 70 to 150C.

11. A process as claimed in claim 1 wherein from 1.5 to 3 moles of said amine or amine mixture is used per mole of dinitro compounds present in the crude mixture, and the treatment is carried out at a temperature of 40C. to 200C.

12. A process as claimed in claim 11 wherein said aprotic organic solvent is selected from the group consisting of an aliphatic or aromatic halogenated hydrocarbon, nitrobenzene, anisole, an aliphatic N,N-dialkylcarboxamide or a mixture thereof.

13. A process as claimed in claim 12 wherein the treatment is carried out at a temperature of 70C. to 

1. A PROCESS FOR THE PRODUCTION OF PURE 1NITROANTHRAQUINONE FROM A CRUDE MIXTURE OF MONO- AND DINITROANTHRAQUINONES WHICH COMPRISES TREATING SAID CRUDE MIXTURE IN AN APROTIC ORGANIC SOLVENT WITH AN ALIPHATIC, CYCLOALIPHATIC, ARALIPHATIC OR SATURATED HETEROCYCLIC PRIMARY OR SECONDARY AMINE OR MIXTURES THEREOF, USING SAID AMINE OR AMINE MIXTURE IN AN AMOUNT OF FROM 0.7 TO 4 MOLES PER MOLE OF DINITRO COMPOUNDS IN THE CRUDE MIXTURE AND CARRYING OUT THE TREATMENT AT A TEMPERATURE OF ABOUT 40*C TO 250*C.
 2. A process as claimed in claim 1 wherein an aliphatic or aromatic halogenated hydrocarbon, nitrobenzene, anisole, an aliphatic N,N-dialkylcarboxamide or a mixture thereof is used as the organic solvent.
 3. A process as claimed in claim 1 wherein N,N-dimethylformamide, N-methylpyrrolidone, anisole, chlorobenzene, nitrobenzene or 1,2-dichloroethane is used as the solvent.
 4. A process as claimed in claim 1 wherein ethanolamine, diethanolamine, butylamine, piperidine, morpholine or a mixture thereof is used as the amine.
 5. A process as claimed in claim 1 wherein the amount of aprotic organic solvent is from 0.5 to 10 times the weight of the nitroanthraquinone mixture.
 6. A process as claimed in claim 3 wherein the amount by weight of solvent is from 0.7 to 3.0 times the weight of the nitroanthraquinone mixture.
 7. A process as claimed in claim 4 wherein from 1.5 to 3 moles of said amine or amine mixture is used per mole of dinitro compounds present in the crude mixture.
 8. A process as claimed in claim 1 wherein the treatment with the amine is carried out at a temperature of from 40* to 200C.
 9. A process as claimed in claim 3 wherein the treatment is carried out at a temperature of from 70* to 150*C.
 10. A process as claimed in claim 7 wherein the treatment is carried out at a temperature of from 70*to 150*C.
 11. A process as claimed in claim 1 wherein from 1.5 to 3 moles of said amine or amine mixture is used per mole of dinitro compounds present in the crude mixture, and the treatment is carried out at a temperature of 40*C. to 200*C.
 12. A process as claimed in claim 11 wherein said aprotic organic solvent is selected from the group consisting of an aliphatic or aromatic halogenated hydrocarbon, nitrobenzene, anisole, an aliphatic N,N-dialkylcarboxamide or a mixture thereof.
 13. A process as claimed in claim 12 wherein the treatment is carried out at a temperature of 70*C. to 150*C. 